超微粉碎玉米秸秆微观结构与秸秆-淀粉共混膜蠕变特性

Microstructure of Ball Milling Cornstalk and Creep Behavior of Corn Starch-based Films

为改善淀粉膜的性能,提高玉米秸秆的利用价值,研究了超微粉碎时间对玉米秸秆微观结构的影响,并选取超微粉碎1 h的玉米秸秆与玉米淀粉共混制备秸秆-淀粉共混膜,研究了超微粉碎秸秆的添加量对淀粉基膜蠕变特性的影响,并进行了模型拟合。超微粉碎试验结果表明,超微粉碎1 h的玉米秸秆维管束结构破坏较为完全,与对照样相比,平均粒径从85.33μm变为9.46μm,结晶度从39.46%变为19.29%。延长超微粉碎时间,秸秆粉体间团聚现象逐渐加剧,最终形成大颗粒团聚体。秸秆-淀粉共混膜蠕变特性测试结果表明,超微粉碎玉米秸秆的添加能显著改善共混膜的粘弹特性和蠕变特性。当添加量不大于15%时,超微粉碎秸秆-淀粉膜的蠕变形变、蠕变柔量和不可恢复形变都会随着添加量的增加而减小。当秸秆添加量达到淀粉用量的20%时,淀粉膜的蠕变特性有减弱的趋势。模型拟合结果表明,Burgers模型能很好地拟合秸秆-淀粉膜的蠕变-恢复测试结果,决定系数均达到0.98以上。

To improve the property of starch film and the additional value of cornstalk,this paper studied the effects of ultrafine grinding time on the composition structure of cornstalk. And 1 h ultrafine grinding cornstalk was selected to prepare films with starch. Then the creep and creep-recovery behavior of starchbased films were investigated,to which different content of ball milling cornstalk was added. The results showed that after 1 h ball-milling,the fiber bundle and the cell wall of cornstalk can be damaged relatively completely. Comparing with control sample,the particle size and crystallinity were decreased significantly,from 85. 33 μm to 9. 46 μm and from 39. 46% to 19. 29%,respectively. However,with the extension of grinding time,the reunion phenomenon was gradually increased,eventually formed larger particles aggregation. The creep and creep-recovery behavior results indicated that the creep deformation,creep compliance,and irreversible deformation were decreased with the increase of the cornstalk content untill reached 15%. When the content was up to 20%,the anti-creep behavior trended to be weaken.Finally,four-component Burgers model was used to fit creep strain and time data( R2> 0. 98).